Tomcat的maxParameterCount&maxPostSize参数

Tomcat的maxParameterCount&maxPostSize参数

参考文章：
嵌入式Tomcat容器的参数(maxParameterCount&maxPostSize)设定，参数过多解决方案

1.问题

1.1问题现象

周五同事说，请求的参数拿不到了。但是同一个接口请求参数太大就没有参数了，参数少的话服务端是有参数的。

打开浏览器的控制台，发现POST的请求参数中的有一个参数很大，所有的参数加起来有2.8M了。网上查了一下Tomcat的配置，
原来配置文件中有一个masPostSize的参数。因此这个博客来看看tomcat的maxParameterCount&maxPostSize参数，看看是不是这个问题导致的。

这里截图看到线上是Content-Type: application/x-www-form-urlencoded;charset=UTF-8的POST请求类型，Content-Length:有问题的是2.8M，并不是这个截图所示的234B。

1.2 参数总结

• maxParameterCount控制请求参数的个数，对于application/x-www-form-urlencoded or multipart/form-data的POST请求来说是请求参数和请求体参数总个数。超出的参数获取不到
• maxPostSize控制POST请求参数大小的限制。
  • application/x-www-form-urlencoded大小超过的参数获取不到。
  • multipart/form-data 大小超过异常报错。

1.3 问题总结

tomcat的maxPostSize没有设置，默认的是2M，请求是application/x-www-form-urlencoded 类型的，所以也不会报错。参数字节数小的可以获取到，参数字节数大的就获取不到了。

2 Tomcat官网的解释

2.1 到https://tomcat.apache.org/找到文档入口

2.2 找到文档的Reference

2.3 查看配置文件的参数

• maxParameterCount
  • The maximum total number of request parameters (including uploaded files) obtained from the query string and, for POST requests, the request body if the content type is application/x-www-form-urlencoded or multipart/form-data. Request parameters beyond this limit will be ignored. A value of less than 0 means no limit. If not specified, a default of 10000 is used. Note that FailedRequestFilter filter can be used to reject requests that exceed the limit.
  • 参数个数，超出的部分会被忽略，默认是1w个参数
• maxPostSize
  • The maximum size in bytes of the POST which will be handled by the container FORM URL parameter parsing. The limit can be disabled by setting this attribute to a value less than zero. If not specified, this attribute is set to 2097152 (2 MiB). Note that the FailedRequestFilter can be used to reject requests that exceed this limit.
  • POST请求体参数的大小，字节单位，这里没说超过了会怎么样。
    

<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  
  
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  
  <GlobalNamingResources>
    
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  GlobalNamingResources>

  
  <Service name="Catalina">

    
    


    
    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443"
               maxPostSize="7"
               maxParameterCount="2"
               />
    
    
    
    
    
    

    
    

    

    
    <Engine name="Catalina" defaultHost="localhost">

      
      

      
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">

        
        

        
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t "%r" %s %b" />

      Host>
    Engine>
  Service>
Server>

3 文档看不明白，自己做实验吧。

    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443"
               maxPostSize="7"
               maxParameterCount="2"
               />

• 参数个数最大2个
• POST请求大小最大7个

3.1 maxParameterCount 参数个数

• GET请求参数的个数超过之后，多出来的就取不到了。

 ~/data/ 
 ~/data/ curl -s  --location 'http://localhost:8080/?m=m&m1=m1&m2=m2' | jq .
{
  "m": [
    "m"
  ],
  "m1": [
    "m1"
  ]
}
 ~/data/ 
 ~/data/ curl -s  --location 'http://localhost:8080/?m=m&m1=m1' | jq .      
{
  "m": [
    "m"
  ],
  "m1": [
    "m1"
  ]
}
 ~/data/ 

• POST的请求参数个数超过过之后，多出来的就取不到了。

 ~/data/ 
 ~/data/ curl -s  --location --request POST 'http://localhost:8080/test?m=m&m1=m1&m2=m2' | jq .
{
  "m": [
    "m"
  ],
  "m1": [
    "m1"
  ]
}
 ~/data/ 
 ~/data/ 
 ~/data/ curl -s  --location --request POST 'http://localhost:8080/test?m=m&m1=m1' | jq .      
{
  "m": [
    "m"
  ],
  "m1": [
    "m1"
  ]
}
 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test?m=m&m1=m1&m2=m2' \
--header 'Content-Type: application/x-www-form-urlencoded' -s \
--data-urlencode 'm3=m3' | jq .
{
  "m": [
    "m"
  ],
  "m1": [
    "m1"
  ]
}
 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test?m=m' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'm3=m3' -s | jq .
{
  "m": [
    "m"
  ],
  "m3": [
    "m3"
  ]
}
 ~/data/ 
 ~/data/ 

3.2 maxPostSizePOST请求参数大小

• Content-Type: application/x-www-form-urlencoded大小没有超过都可以获取到，超过大小都获取不到

 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test' -s \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'j=12345' | jq .
{
  "j": [
    "12345"
  ]
}
 ~/data/ 
 ~/data/ 
 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test' -s \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'j=123456' | jq .
{}
 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test' -s \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'j=1' \
--data-urlencode 'i=2' | jq .
{
  "j": [
    "1"
  ],
  "i": [
    "2"
  ]
}
 ~/data/ 
 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test' -s \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'j=1' \
--data-urlencode 'i=23' | jq .
{}
 ~/data/ 
 ~/data/ 

• multipart/form-data; boundary= 大小没有超过都可以获取到，超过大小报错

 ~/data/ 
 ~/data/ curl --location 'http://localhost:8080/test' \
--form 'j="1234"' -s | jq . 
{
  "j": [
    "1234"
  ]
}
 ~/data/ curl --location 'http://localhost:8080/test' -s \
--form 'j="12345"'|jq .
{
  "timestamp": 1705816422926,
  "status": 500,
  "error": "Internal Server Error",
  "exception": "org.springframework.web.multipart.MultipartException",
  "message": "Could not parse multipart servlet request; nested exception is java.lang.IllegalStateException: The multi-part request contained parameter data (excluding uploaded files) that exceeded the limit for maxPostSize set on the associated connector",
  "path": "/test"
}
 ~/data/ 

4.实验配置

 ~/data/  docker pull tomcat:8.5.98
 ~/data/  docker run -d -p 8080:8080 -v /Users/admin/data/tomcat/webapps:/usr/local/tomcat/webapps tomcat:8.5.98
90f2cfa859c67e3886f67d8b862005c196944cbc037efc64e2e1417b450ae174
 ~/data/ server.xml的配置见上文
 ~/data/ docker cp ./server.xml 90f2cfa859c6:/usr/local/tomcat/conf/server.xml
 ~/data/ java 代码：https://github.com/xiaolixi/spring/tree/main/springboot-resttemplate

https://tomcat.apache.org/tomcat-8.5-doc/servletapi/javax/servlet/ServletRequest.html#getParameterMap()